Applicant's U.S. Pat. No. 4,026,564 issued May 31, 1977 discloses a face seal in which an eccentric annular seal face of the stator is resiliently urged against the seal face of the rotor. Such eccentric design provides improved lubrication and cooling of the contacting seal faces. Although seal performance is improved by such an arrangement, it is difficult to eliminate leakage entirely due to seal face convergence or separation resulting from heat distortion, wear, etc.
U.S. Pat. No. 4,407,509 issued Oct. 4, 1983 to I. Etsion, discloses a face seal purporting to provide zero-leakage. The disclosed device uses gap widths of different size associated with annular arcs forming a closed curve. The patent also discloses an embodiment with an eccentric circular face, but it does not disclose how proper alignment of the seal faces to maintain the desired gaps is to be maintained. Also, the disclosed device, because of the gaps, allows leakage at standstill or low speed, for which it is suggested an additional barrier may be provided.